1. Field of the Invention
The present invention relates to an ink cartridge adapted for an ink jet printer, and particularly relates to an ink cartridge that can improve the ink leakage problem at both the inlet and outlet of ink cartridge.
2. Background of the Invention
The ink jet recording technology is such as to record characters and images directly on a recording medium (such as paper, cloth, or plastic sheet) by discharging ink from fine nozzles thereto. Conventionally, the recording apparatus has been utilized as a printer serving and provided as the output terminal of a copying machine, a facsimile equipment, a printer, a word processor, a work station or the like; or as a handy or portable printer used for such an information processing system as a personal computer, a host computer, an optical disc device or a video apparatus. In a conventional recording apparatus, ink is supplied to a recording head from an ink tank constructed as a cartridge.
Although increasing the negative pressure prevents ink from seeping out of the recording head, the negative pressure has an upper limit. If the negative pressure is too high, ink cannot overcome the negative pressure and jet from the recording head. On the other hand, the ink cartridge must be able to adjust the negative pressure in the ink tank automatically by keeping the negative pressure during a suitable range. U.S. Pat. No. 6,783,219 B2, entitled “Ink Cartridge”, one of the relative documents, provides an elastic member for unidirectional ventilation by a pressure difference between inside and outside the hollow ink tank body without both air inlet hole and porous member. A pressure regulator referred in the prior art is used to maintain the pressure and the ink flows to the printhead continuously. Nevertheless, ink leakage problems of the pressure regulator may occur during storage, delivery and printing operation. Alternatives of regulator pressure have been explored but have failed to adequately address the leakage issue.
It is desirable to develop a new and improved ink cartridge to substantially resolve the leakage problems and provide better, more advantageous overall results.